Sulfur-impregnated and coupling agent-reacted organoclay mercury and/or arsenic ion removal media

ABSTRACT

The use of two mercury and arsenic removal media: A) a sulfur-impregnated organoclay; and B) a coupling agent-reacted organoclay, wherein the coupling agent preferably contains a mercapto, disulfide, tretrasulfide and/or polysulfide end group provides mercury removal media having increased reactivity, stability, and synergistic mercury removal ability. The preferred mercury removal media described herein is prepared by reacting an organophilic clay containing onium ions A) with elemental sulfur; and B) with a sulfur-containing coupling agent, preferably containing a mercapto, disulfide, tetrasulfide, and/or polysulfide moiety.

FIELD OF THE INVENTION

The present invention is directed to compositions; methods ofmanufacturing the compositions; and methods of using the compositionsfor removing mercury (organic mercury, Hg, Hg⁺; and/or Hg⁺²) and/orarsenic (As⁺³ and/or As⁺⁵) from water. The compositions, also identifiedherein as “media”, or “mercury removal media”, or “arsenic removalmedia”, or “Hg/As removal media”, can be used to remove mercury and/orarsenic from any water source and is particularly useful for removal ofmercury and/or arsenic from drinking water; industrial wastewater;contaminated groundwater; contaminated sediment; offshore producedwater, so that the produced water can be returned to the ocean; and forremoval of mercury and/or arsenic from aqueous mining wastes. The Hg/Asremoval media comprises a combination of two Hg/As removal media: (1) ahomogeneous, preferably extruded composition comprising a layeredphyllosilicate, elemental sulfur (free state sulfur), and an organicphyllosilicate surface treating agent, preferably an onium cation,resulting in an organoclay containing sulfur and (2) a homogeneous,preferably extruded composition comprising a layered phyllosilicatecoupled to a coupling agent containing a mercapto or sulfide reactantgroup, and an organic phyllosilicate surface-treating agent, preferablyan onium cation, resulting in an organoclay containing sulfur. In bothmedia, the sulfur is bonded to the phyllosilicate covalently, ionically,physically, or by a combination of mechanisms.

BACKGROUND AND PRIOR ART

The technologies available for mercury and arsenic removal, such asprecipitation, coagulation/co-precipitation, activated carbonadsorption, ion-exchange and the like, are not sufficiently effectivefor mercury and arsenic (arsenite and arsenate compounds) removal. Thisassignee's organoclay has been proven effective on a variety of organiccontaminants in the last decade. See, for example, this assignee's U.S.Pat. Nos. 6,398,951; 6,398,966; 6,409,924; and 6,749,757, incorporatedherein by reference. A new Hg/As filtration media, described herein, canbe operated in a similar fashion, or together with the organoclay media,but is much more effective for mercury or arsenic removal.

Both Hg/As removal media described herein have a similar physical formto the organoclays used for organic contaminant removal and can besimilarly packed in a canister or cartridge, as described in theabove-listed patents. In addition, the Hg/As removal media describedherein can be deployed in single layer or multi-layer water-permeablemats, as described in this assignee's published applications Ser. No.10/718,128, filed Nov. 19, 2003 (Publication No. 2005-01013707 A1), Ser.No. 11/221,019, filed Sep. 7, 2005 (Publication No. 2006/0000767 A1),[Ser. No. 11/489,383, filed Jul. 19, 2006, (Publication No. 2006-0286888A1)], Ser. No. 11/599,080, filed Nov. 14, 2006 (Publication No.2007-0059542 A1); and Ser. No. 11/741,376, filed Apr. 27, 2007, all ofwhich are hereby incorporated by reference. Fundamentally, the Hg/Asremoval media is based on organoclay technology but it has beensubstantially modified using several unique chemistries to enhanceadsorption of mercury and arsenic-containing compounds. The mechanism ofmercury adsorption is based upon chemical bonding, ionic bonding,mechanical bonding, or a combination thereof. The mercury and/or arsenicwill be bonded to the media's external and internal surfaces and thebonding process is non-reversible.

Both Hg/As removal media described herein are effective on all sourcesof mercury and arsenic including organic types of mercury and arsenic,including organic mercury and arsenic compounds, mercury metal (zerovalent); arsenite and arsenate compounds; arsenic ions (both III and Vvalent); and mercury ions (both I and II valent). When the organic-basedmercury and/or arsenic is involved, the adsorption mechanism ofpartition could be involved in addition to chemical bonding. Inaddition, both Hg/As removal media described herein also are effectiveto remove oil, grease and other organic contaminant molecules. The mediawill be spent eventually when all of the adsorption sites are saturated.The actual media life will depend on the contaminated water compositionsand the field operation conditions. When both Hg/As removal media areused together, either in series or admixed, the removal of mercuryand/or arsenic is synergistic.

Greco U.S. Pat. No. 5,512,526 describes a clay-based heavy metal removalmedia prepared by reacting a fatty mercaptan, e.g., dodecylmercaptan,with a fatty alkyl-containing quaternary ammonium compound. Asdescribed, the mercaptan's hydrophobic fatty alkyl group associates insome manner with the fatty alkyl group of the quaternary ammoniumcompound.

SUMMARY

It has been found in accordance with the present invention that thecombined use of (1) a sulfur-impregnated organoclay; and (2) a couplingagent-reacted organoclay, wherein the coupling agent contains sulfur,preferably in the form of a mercapto, disulfide, tretrasulfide and/orother polysulfide functional group (hereinafter called “couplingagent-reacted”) provides mercury and arsenic removal media havingincreased reactivity, stability, and synergistic mercury and arsenicremoval ability. The first (sulfur-impregnated) Hg/As removal mediadescribed herein is prepared by impregnating an organophilic clay withelemental (free state) sulfur; and the second Hg/As removal mediadescribed herein is prepared by reacting an organophilic clay,preferably containing onium ions, with a sulfur-containing couplingagent, preferably containing a mercapto, disulfide, tetrasulfide, and/orpolysulfide moiety. Alternatively, a clay can be made organophilic bytreating the clay with a surface-treating agent, such as a polymercapable of increasing the d-spacing of the clay platelets, or preferablywith onium ions, prior to or simultaneously with (1) impregnating theresulting organoclay with sulfur, or (2) reacting the organoclay with asulfur-containing coupling agent.

BRIEF DESCRIPTIONS OF THE DRAWINGS

FIGS. 1 and 2 are graphs showing the mercury removal efficacy of thesulfur-impregnated Hg/As removal media described in the examples;

FIG. 3 is a graph showing the arsenic removal results for the Hg/Asremoval media of Example 6;

FIGS. 4-6 are graphs showing the mercury removal efficacy of thecoupling agent-reacted media described in the examples;

FIG. 7 is a side view of an offshore oil well drilling platformgenerally showing one or both of the Hg/As removal media held within acanister attached to an offshore oil well drilling platform supportstructure with an alternative placement of a sump tank;

FIG. 8 is a sectional view of an embodiment of a vessel containing aplurality of Hg/As removal media-containing cartridges or canisters forefficient removal of mercury and arsenic contained in water;

FIG. 9 is an elevational view of a preferred embodiment of a vesselcontaining a plurality of Hg/As removal media-containing cartridges orcanisters;

FIG. 10 is a top plan view of the header of the vessel shown in FIG. 9and openings within the header for receiving permeable conduits each ofwhich can extend through a stack of cartridges or canisters as shown inFIGS. 8 and 9;

FIG. 11 is a partially broken-away side view of an embodiment of a Hg/Asremoval media-containing vessel, containing multiple, stacked cartridges(FIGS. 8 and 9); and

FIG. 12 is an elevational view of a preferred embodiment of a mercuryremoval media-containing cartridge shown in FIGS. 8 and 9.

It should be understood that the drawings are not necessarily to scaleand that the embodiments are sometimes illustrated by graphic symbols,phantom lines, diagrammatic representations and fragmentary views. Incertain instances, details which are not necessary for an understandingof the present invention or which render other details difficult toperceive may have been omitted. It should be understood, of course, thatthe invention is not necessarily limited to the particular embodimentsillustrated herein.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

It should be understood that while the following description of thepreferred embodiment of the invention is directed to the use of themethods, apparatus and mercury/arsenic removal media on an offshoredrilling platform, the invention is also useful for mercury and arsenicremoval from any contaminated water, including drinking water;industrial wastewaters; contaminated ground water supplies; aqueousmining wastes; and contaminated underwater and soil sediments,particularly when contained in a reactive mat, as described in theapplications identified in paragraph [0003], or when used in bulk form.

The sulfur-impregnated Hg/As removal media described herein is asulfur-containing layered organophilic phyllosilicate that is (or hasbeen) made organophilic by reaction with an organic phyllosilicatesurface-treating agent, preferably an onium ion-liberating compound, andhas been made mercury-reactive and arsenic reactive by impregnation withelemental sulfur. The coupling agent-reacted Hg/As removal mediadescribed herein preferably is a mercapto- or sulfide-containing layeredorganophilic phyllosilicate that is (or has been) made organophilic byreaction with an organic phyllosilicate surface-treating agent,preferably an onium ion-liberating compound, and has been mademercury-reactive and arsenic-reactive by bonding a mercapto- orsulfide-containing coupling agent to the phyllosilicate platelets.

Phyllosilicate

The phyllosilicate can be a smectite clay, e.g., bentonite,montmorillonite, hectorite, beidellite, saponite, nontronite,volkonskoite, sauconite, stevensite, and/or a synthetic smectitederivative, particularly fluorohectorite and laponite; a mixed layeredclay, particularly rectonite and their synthetic derivatives;vermiculite, illite, micaceous minerals, and their syntheticderivatives; layered hydrated crystalline polysilicates, particularlymakatite, kanemite, octasilicate (illierite), magadiite and/or kenyaite;attapulgite, palygorskite, sepoilite; or any combination thereof.

Clay Surface Modification Agents

The surface modification (intercalant) agents used for organoclayformation include but are not limited to primary amine, secondary amine,tertiary amine, and onium ions and/or onium salt compounds, polyquat,polyamine, cationic polymers and their derivatives, nonionic polymers,and mixture of thereof.

In the wet process, the surface modification agent, e.g., onium ion, isintroduced into the layered material galleries in the form of a solid orliquid composition (neat or aqueous, with or without an organic solvent,e.g., isopropanol and/or ethanol, if necessary to aid in dissolving theonium ion compound) having a surface modification, e.g., onium ionconcentration sufficient to provide a concentration of about 5% to about10% by weight clay (90-95% water) and the surface modification agent,e.g., onium ion compound, is added to the clay slurry water, preferablyat a molar ratio of onium ions to exchangeable interlayer cations of atleast about 0.5:1, more preferably at least about 1:1. The oniumion-intercalated clay then is separated from the water easily, since theclay is now hydrophobic, and dried in an oven to less than about 5%water, preferably bone dry. The onium ion surface modification agentcompound or polymer can be added as a solid with the addition to thelayered material surface modification agent blend of preferably about20% to about 40% water and/or organic solvent, more preferably at leastabout 30% water or more, based on the dry weight of layered material.Preferably about 30% to about 40% water, more preferably about 25-35%water, based on the dry weight of the layered material, is included inthe onium ion intercalating composition, so that less water is sorbed bythe intercalate, thereby necessitating less drying energy after oniumion intercalation.

In general, a dry process can be described, as follows, for organoclaymedia preparation or manufacturing. The powder form of clay mineral isfed into a mixer through a major port for solids, typically an extruder.A separate port for the 2^(nd) powder form of solid can also be usedbesides the clay feeding port. The liquid forms of the additives,including water, intercalant agent, and the coupling agent if any, arefed into the mixer through the separate ports. Either multiple forms ofthe solids or the liquids could be pre-mixed, or both the solids and theliquids can be pre-mixed through a separate mixer, before they are fedinto the extender. A preferred liquid weight is from 10% to 50% based onthe total mixture weight, more preferably from 20% to 40%, mostpreferably from 25% to 35%. The intimate mixture from the extruder willbe further dried through a dryer, and be ground to the preferredparticle size. A screening process could be used to collect the finishedproduct in the desired particle size distribution.

The onium ions may generally be represented by the following formula:

The preferred phyllosilicate surface-treating agent is one or more oniumsalt compounds, generally represented by the following formula:

wherein Q=N, P, S;

-   wherein A=halide, acetate, methylsulfate, hydroxide, preferably    chloride;-   wherein R₁, R₂, R₃ and R₄ are independently organic moieties, or    oligomeric moieties or hydrogen. (Ref. U.S. Pat. No. 6,376,591),    hereby incorporated by reference. Examples of useful organic    moieties include, but not limited to, linear or branched alkyl,    benzyl, aryl or aralkyl moieties having 1 to about 24 carbon atoms.

EXAMPLES

bis(hydrogenated tallow alkyl)dimethyl ammonium chloride (Arquad® 2HT);benzylbis(hydrogenated tallow alkyl)methyl ammonium chloride (Arquad®M2HTB); benzyl(hydrogenated tallow alkyl)dimethyl ammonium chloride(Arquad® DMHTB); trihexadecylmethyl ammonium chloride (Arquad® 316);tallowalkyl trimethyl ammonium chloride (Arquad® T-27W and Arquad®T-50); hexadecyl trimethyl ammonium chloride (Arquad® 16-29W and Arquad®16-50); octadecyl trimethyl ammonium chloride (Arquad® 18-50(m)); anddimethylhydrogenated tallow-2-ethyhexly ammonium methylsulfate.

Additional phyllosilicate surface-treating agents include the materialsset forth below in paragraphs [0024]-[0030].

Quaternary ammonium ions containing ester linkage: (ref. U.S. Pat. No.6,787,592, hereby incorporated by reference, see columns 5 and 6)

EXAMPLE

di(ethyl tallowalkylate)dimethyl ammonium chloride (Arquad® DE-T).

Quaternary ammonium ions containing amide linkage: (ref. US patentapplication 2006/0166840 hereby incorporated by reference, see page 2)

The onium ions may be functionalized such as protonated α,ε-amino acidwith the general formula (H₃N—(CH₂)_(n)—COOH)⁺.

Alkoxylated quaternary ammonium chloride compounds (ref. U.S. Pat. No.5,366,647 hereby incorporated by reference)

EXAMPLES

cocoalkylmethylbis(2-hydroxyethyl) ammonium chloride (Ethoquad® C/12);octadecylmethyl[polyoxyethylene(15)]ammonium chloride (Ethoquad® 8/25);and octadecylmethyl (2-hydroxyethyl) ammonium chloride (Ethoquad 18/12).

Polyquat (U.S. Pat. No. 6,232,388, hereby incorporated by reference)

EXAMPLE

N,N,N′,N′,N′-pentamethyl-N-tallowalkyl-1,3-propane diammonium dichloride(Duaquad® T-50).

Polyamine: (ref. US patent application 2004/0102332 hereby incorporatedby reference)

EXAMPLES

N-tallow-1,3-diaminopropane (Duomeen® T); N-tallowalkyl dipropylenetriamine (Triameen® T); and N-tallowalkyl tripropylene tetramine(Tetrameen® T).

Cationic polymers, non-ionic polymers, including homopolymer orcopolymer, low molecular weight or high molecular weight

EXAMPLE

Polydiallydimethylammonium chloride;Poly(dimethylamine-co-epichlorohydrin); Polyacrylamide; and Copolymersof acrylamide and acryloyloxylethyltrimethyl ammonium chloride.

Coupling Agent

Examples of the preferred silane coupling agents containing a mercapto,disulfide, tetrasulfide, or polysulfide reactant group or moiety forreaction with the organoclay in manufacturing the coupling agent-reactedHg/As removal media include, for example,3-Mercaptopropyltrimethoxysilane; 3-Mercaptopropyltriethoxysilane;3-Mercaptopropylmethyldimethoxysilane;(Mercaptomethyl)dimethylethoxysilane;(Mercaptomethyl)methyldiethoxysilane;11-mercaptoundecyltrimethoxysilane;Bis[3-(triethoxysilyl)propyl]-tetrasulfide;Bis[3-(triethoxysilyl)propyl]-disulfide;Bis-[m-(2-triethoxysily)lethyl)tolyl]-polysulfide; and mixtures thereof.

Hg/As Removal Media

In a preferred embodiment, particularly in offshore environments, thecombined use of both Hg/As removal media described herein can be usedafter the use of an organoclay for removal of organics in order toprotect and extend the active life of both the organoclay, in an initialorganoclay stage, and the two Hg/As removal media, used after organiccontaminant removal. An operation procedure using an initial organoclaymedia followed by contact with both of the Hg/As removal media, inseries, is highly effective. A carbon media can also be used before orafter both Hg/As removal media, if necessary. In general, the retentiontime of contact between Hg-contaminated or As-contaminated water andeach of the Hg/As removal media should be no less than about 10 seconds,preferably at least about 1 minute, more preferably about 2 minutes ormore.

The preferred amount of components of the sulfur-impregnated organoclaymedia is as follows:

Phyllosilicate Intercalant Agent Elemental Sulfur Preferably  1-90 10-500.5-50   More Preferably 35-83 15-45 2-20 More Preferably 50-77 20-403-10 More Preferably 59-71 25-35 4-6  Most Preferably 65 30 5

The preferred amounts of components that form the coupling agent-reactedorganoclay Hg/As removal media are as follows:

Phyllosilicate Intercalant Agent Coupling Agent Preferably  1-90 10-500.5-50   More Preferably 35-83 15-45 2-20 More Preferably 50-77 20-402-12 More Preferably 59-71 25-35 5-9  Most Preferably 65 28 7

Laboratory Study

A column study was conducted in order to demonstrate thesulfur-impregnated Hg/As media's ability to remove mercury (Examples1-5); arsenic (Example 6); and a combination of mercury and arsenic(Example 7). The influent was composed of ˜10 ppm of Hg(NO₃)₂ solutionwith dilute nitric acid matrix. The effluent samples were taken atregular intervals and the mercury content was measured by an ICPanalytical test. The flow rate was about 10 bed volumes (BV) per hour,using a 6-minute retention time. The effluent curve is shown in FIG. 1.A commercial mercury removal media (Hg-A of SME Associates, Houston,Tex.) containing a mixture of 85-90% activated carbon and 10-15% sulfurwas also included in this study for comparison purposes, as shown inFIG. 1.

Although only a dry-process is described in the following examples, awet-process is also suitable as the process to make thesulfur-impregnanted mercury media described herein.

Example 1 Sample L1S

400.0 g of bentonite clay (particle size<75 μm preferred, and ˜8%moisture content) was dry-mixed with 28.75 g of sulfur in the powderform (purchased from Aldrich) using the Kitchen Aid mixer for oneminute. 80.0 g of deionized water was added to this bentonite-sulfurmixture slowly under shearing using the same mixer and mixed for ˜2minutes. 209.6 g of melt quat (ARQUAD® 2HT from Akzo Nobel,bis(hydrogenated tallow alkyl)dimethyl ammonium chloride, ˜83% active )was added to this clay-sulfur-water mixture under shearing using thesame mixer, and mixed for 5 minutes. The mixture was extruded threetimes using a laboratory-scale extruder with a die-plate, and the finalextrudates were oven-dried at 85° C. to a moisture content of less than5% by weight. The dried extrudates were ground and resulting particlesbetween 18 and 40 mesh (US standard sieves) were collected and testedfor their performance.

Example 2

The media material collected in Example 1 was packed in a column havingan inner diameter of 1.5″ and having an empty bed volume (BV) of ˜86 mL.The influent was composed of ˜10 ppm of Hg(II) in the presence of nitricacid. The effluent samples were taken at regular intervals and themercury content was measured by the Inductively Coupled Plasma (ICP)analytical technique. The flow rate was about 10 BV/hr with a 6-minuteretention time. The effluent data is plotted in FIG. 1. A commercialorganoclay media Hg-A (without sulfur) is also included in this studyfor the comparison purpose.

Example 3 Production Trial 1

Bentonite powder and sulfur powder (from Harwick Standard DistributionCorporation, grade 104) were blended in a ratio of 93.3:6.7 by weight,and then this mixture was fed into a 5″ Readco continuous processor at afeed rate of 900 lb/hr. About 0.25 gallon/minute of water and 1.04gallon/minute of quat (ARQUAD® 2HT from Akzo Nobel, bis(hydrogenatedtallow alkyl)dimethyl ammonium chloride, ˜83% active) were also fed inthe Readco processor through two independent ports in sequence. Thedischarged extrudates from the processor were sent to a dryer, the driedextrudates were further milled and the granular particles between 18 and40 mesh with moisture content less than 5% by weight were colleted asthe finished product.

Example 4

A similar column test as described in Example 2 was conducted on theproduct sample collected in Example 3. The effluent testing results areplotted in FIG. 2.

Example 5

The media described in Example 2 was tested under offshore platformconditions using actual offshore mercury-contaminated water. Acommercial available organoclay product, CrudeSorb™, was also used infront of this Hg/As removal media. The influent had a mercuryconcentration of 11.4 ppb, and the effluent was 3.4 and 3.9 ppb afterthe 30 minutes and 90 minutes treatment, respectively. A total mercuryremoval efficiency of >65% was achieved.

Arsenic Removal Example Example 6

The media described in Example 3 was examined for its ability to removearsenic. The media materials were packed in a column with inner diameterof 1.5″ and empty bed volume of ˜86 mL. The influent solution wascomposed of ˜5 ppm of As(V). The As(V) stock solution was prepared bydissolving Na₂HAsO₄.7H₂O in the de-ionized water. The effluent sampleswere taken at regular intervals and the arsenic content was measured bythe Inductively Coupled Plasma (ICP) analytical technique. The flow ratewas around 10 BV/hr with 6-minute retention time. The effluent data isplotted in FIG. 3.

Offshore Field Study—Sulfur-Impregnated Media Example for Both Hg and AsRemoval: Example 7

The sulfur-impregnated media material described in Example 3 was testedunder offshore platform conditions using the actual wastewatercontaminated by both mercury and arsenic. The contaminated water waspumped through two columns in series. Each column had a diameter of 3″and held about 1.5 Liter of media (˜1,125 grams). The first column waspacked with the commercial available organoclay media, CrudeSorb™, andthe second column was packed the media material described in Example 3.The retention time was roughly equal to 5-minutes. The influent hadmercury and arsenic concentration of 11.4 ppb and 7.55 ppb,respectively. After the 30 minutes and 90 minutes treatment, theeffluent had mercury concentrations of 3.4 ppb and 3.9 ppb, arsenicconcentrations of 5.18 ppb and 5.16 ppb, respectively. So a totalmercury and arsenic removal efficiency of greater than 65% and 30% wereachieved, respectively.

Another column study was conducted in order to demonstrate the couplingagent-reacted Hg/As media's ability to remove mercury (Examples 8-18);arsenic (Examples 19 and 20); and a combination of mercury and arsenic(Example 21). The influent was composed of ˜10 ppm of Hg(NO₃)₂ solutionwith dilute nitric acid matrix. The effluent samples were taken atregular intervals and the mercury content was measured by an ICPanalytical test. The flow rate was about 10 BV/hr using a 6-minuteretention time. The effluent curve is shown in FIG. 4. A commercialmercury removal media (Hg-A of SME Associates, Houston, Tex.) containinga mixture of 85-90% activated carbon and 10-15% sulfur was also includedin this study for comparison purpose, as shown in FIG. 4.

Although only a dry-process is described in the following examples, awet-process is also suitable as the process to make the couplingagent-reacted mercury media described herein.

Example 8 Sample L6L

800.0 g of bentonite clay (particle size <75 μm preferred, and ˜8%moisture content) was mixed with 160.0 g of deionized water using theKitchen Aid mixer until a homogenous mixture was obtained. 380.0 g ofmelt quat (ARQUAD® 2HT from Akzo Nobel, bis(hydrogenated tallowalkyl)dimethyl ammonium chloride, ˜83% active) was added to thisbentonite-water mixture under shearing using the same mixer, and mixedfor 5 minutes. 40.0 g of the silane agent (Silquest® A-189 from GESilicones, gamma-Mercaptopropyltrimethoxysilane) was pre-mixed with 20.0g of ethanol and 2.0 g of water. This fresh prepared solution was addedto the above clay-water-quat mixture, and mixed for 5 minutes. Thismixture was extruded three times using a laboratory-scale extruder witha die-plate, and the final extrudates were oven-dried at 85° C. to amoisture content of less than 5% by weight. The dried extrudates wereground and resulting particles between 18 and 40 mesh (US standardsieves) were collected and tested for their performance.

Example 9 Sample L6L2

Very similar preparation procedure was conducted except 80.0 g of thesilane agent was pre-mixed with 80.0 g of ethanol and 8.0 g of water,and was subsequently added to clay-water-quat mixture.

Example 10 Sample L6L3

800.0 g of bentonite clay (particle size <75 μm preferred, and ˜8%moisture content) was mixed with 160.0 g of deionized water using thekitchen Aid mixer until a homogenous mixture was obtained. 60.0 g of thesilane agent (Silquest® A-189 from GE Silicones,gamma-Mercaptopropyltrimethoxysilane) was mixed with 380.0 g of meltquat (ARQUAD® 2HT from Akzo Nobel, bis(hydrogenated tallowalkyl)dimethyl ammonium chloride, ˜83% active), and this mixture wasadded to the bentonite-water mixture under shearing using the samemixer, and mixed for 5 minutes. This mixture was extruded three timesusing a laboratory-scale extruder with a die-plate, and the finalextrudates were oven-dried at 85° C. to a moisture content of less than5% by weight. The dried extrudates were ground and resulting particlesbetween 18 and 40 mesh (US standard sieves) were collected and testedfor their performance.

Example 11

The media material collected in Example 1 was packed in a column with aninner diameter of 1.5″ and having an empty bed volume (BV) of ˜92 mL.The influent was composed of ˜10 ppm of Hg(II) in the presence of nitricacid. The effluent samples were taken at regular intervals and themercury content was measured by the Inductively Coupled Plasma (ICP)analytical technique. The flow rate was about 10 BV/hr with a 6-minuteretention time. The effluent data is plotted in FIG. 4. A commercialorganoclay media is also included in this study for the comparisonpurpose.

Examples 12, 13

Column tests were also conducted on the organoclay media materialscollected from Examples 9 and 10. The results are also plotted in FIG.4.

Example 14

A column test was conducted on the organoclay media collected in Example9. The influent was composed of ˜10 ppm of Hg(II) and ˜8 ppm ofmechanical emulsified motor oil. The oil concentration in influent andeffluent was characterized by Total Oil & Grease (TOG) analytical test.Throughout the test, the TOG for effluent was maintained at 0 ppm. Theeffluent results on mercury were plotted in FIG. 5.

Example 15

A column test was conducted on the organoclay media collected in Example9. The influent was composed of 224 ppb of Hg(II). The effluent sampleswere taken at 9.4, 18.9, 28.3 Bed Volume intervals and their mercuryconcentration were 1.2 ppb, 0.8 ppb and 0.3 ppb, respectively. Themercury measurement tests were conducted by Test America (Buffalo Grove,Ill.) using EPA 245.2 test method.

Example 16 Sample Production Trial 2

Bentonite powder was fed into a 5″ Readco continuous processor at a feedrate of 600 lb/hr. About 0.40 gallon/minute of water and 0.78gallon/minute of combined mixture of quat and silane coupling agent werealso fed in the Readco processor through two independent ports insequence. The mixed ratio between the quat (ARQUAD® 2HT from Akzo Nobel,bis(hydrogenated tallow alkyl)dimethyl ammonium chloride, ˜83% active)and the silane coupling agent (Silquest® A-189 from GE Silicones,gamma-Mercaptopropyltrimethoxysilane) was abut 82.6:17.4 by weight. Thedischarged extrudates from the processor were sent to a dryer, the driedextrudates were further milled and the granular particles between 18 and40 mesh with a moisture content less than 5% by weight were colleted asthe finished product.

Example 17

A similar column test as described in Example 11 was conducted on theproduct sample collected in Example 16. The effluent testing results areplotted in FIG. 3.

Example 18

The Hg/As removal media described in Example 16 was tested underoffshore platform conditions using the actual offshore mercurycontaminated water. A commercially available organoclay product,CrudeSorb™, was also used in front of this Hg/As removal media. Theinfluent had a mercury concentration of 37.7 ppb, and the effluent was2.8 and 4.2 ppb after the 30-minute and 90-minute treatment,respectively. A total mercury removal efficiency of >88% was achieved.

Arsenic Removal Example Example 19

The media described in Example 16 was examined for its ability to removearsenic. The media materials were packed in a column having an innerdiameter of 1.5″ and empty bed volume of ˜86 mL. The influent solutionwas composed of ˜5 ppm of As(V). The As(V) stock solution was preparedby dissolving Na₂HAsO₄.7H₂O in the de-ionized water. The effluentsamples were taken at regular intervals and the arsenic content wasmeasured by the Inductively Coupled Plasma (ICP) analytical technique.The flow rate was around 10 BV/hr with 6-minute retention time. During90 bed volume treatment, the average effluent concentration was 3 ppmfor a 40% removal of arsenic by the media.

Offshore Field Study Example for Both Hg and As Removal: Example 20

The media material described in Example 16 was tested under offshoreplatform conditions using the actual wastewater contaminated by bothmercury and arsenic. The contaminated water was pumped through twocolumns in series. Each column had a diameter of 3″ and held about 1.5Liter of media (˜1,125 grams). The first column was packed with thecommercial available organoclay media, CrudeSorb™, and the second columnwas packed the media material described in Example 9. The retention timewas roughly equal to 5-minute. The influent had mercury and arsenicconcentration of 37.7 ppb and 8.17 ppb, respectively. After the 30minutes and 90 minutes treatment, the effluent had mercuryconcentrations of 2.8 ppb and 4.2 ppb, arsenic concentrations of 5.70ppb and 5.87 ppb, respectively. So a total mercury and arsenic removalefficiency of greater than 88% and 28% were achieved, respectively.

Example for Sulfur-Impregnated Media and Coupling Agent-Reacted MediaCombined Use: Example 21

The sulfur impregnated organoclay media and the coupling agent-reactedorganoclay media were tested as a package using the actual wastewatercontaminated by both mercury and arsenic species on an offshoreplatform. The contaminated water was pumped through two columns in aseries operation. Each column had a diameter of 3″ and held about 1.5Liter of media (˜1,125 grams). The first column was packed with thesulfur impregnated organoclay media as described in Example 3, and thesecond column was packed with the coupling agent-reacted organoclaymedia as described in Example 16. The retention time was roughly equalto 5-minute. The influent had mercury and arsenic concentrations of 26.8ppb and 10.68 ppb, respectively. After the 30 minutes treatment, theeffluent had mercury and arsenic concentrations of 2.4 ppb and 2.15 ppb,respectively. So a total, and synergistic mercury and arsenic removalefficiency of greater than 91% and 79% were achieved, respectively.

Turning now to the offshore drawings, and initially to FIG. 7, there isshown an offshore drilling platform generally designated by referencenumeral 10 including a work deck support structure 12 for supporting aplurality of stacked work decks at a substantial height above an oceanwater level 14. The work decks commonly include a cellar deck 16 at alowest work deck level, a second deck 18 located directly above thecellar deck 16, a third deck 20 disposed directly above deck 18, and amain deck 22 at an uppermost work deck level. In extant offshoredrilling platforms, a sump tank 24 has been connected to the drillingplatform 10 at the cellar deck level 16 and rainwater, includingentrained hydrocarbons, particularly oil, paraffins and surfactants havebeen directed from all deck levels, which are contained so thatrainwater and entrained hydrocarbons do not spill over to the ocean, todrain by gravity into the sump tank 24. As described in this assignee'sU.S. Pat. Nos. 6,398,951; 6,398,966; 6,409,924; and 6,749,757,hereinafter incorporated by reference, further separation ofhydrocarbons from rainwater, in addition to gravity separation, isrequired for effective elimination of ocean water hydrocarboncontamination by providing a secondary hydrocarbon recovery apparatuscontaining an organo-clay after the produced water and/or rainwater hasbeen separated by gravity in the sump tank 24 or 24A. In the preferredembodiment of mercury and/or arsenic removal using the methods andapparatus described herein for mercury and arsenic removal offshore, oneor more canisters (not shown) containing an organoclay, for hydrocarbonremoval, is used in series with one or more canisters containing theHg/As removal media (in any order). It is preferred to remove thehydrocarbons with organoclay-containing canister(s) prior to mercuryand/or arsenic removal with Hg/As removal media-containing cartridges.

In accordance with a preferred embodiment of the methods, apparatus andHg/As removal media described herein, it has been found that theapparatus and methods described herein function best, in offshoreplatform use, when the sump tank 24A is disposed on or near a boatlanding deck level 26 (FIG. 7) of the offshore drilling platform 10.However, the sump tank can also be disposed at an upper level, such asat reference numeral 24 in FIG. 7.

Mercury and/or arsenic from ocean water that is collected on theproduction decks 16, 18, 20 and 22 that may accumulate during dryweather on the inner surfaces of the conduit 28 and inner surfaces ofsump tank 24 can be separated from the water that flows from the decksto the Hg/As removal media-containing cartridge 44 for recovery andseparation in accordance with the apparatus and methods describedherein.

Water containing mercury and/or arsenic is conveyed via conduit 28 fromthe deck areas 16, 18, 20 and 22 along the platform infrastructure orsupport leg 12 down to the sump tank 24 or 24A, preferably sump tank 24Afor convenient servicing and/or Hg/As removal media cartridgereplacement. As stated in this assignee's U.S. Pat. Nos. 6,398,951,6,398,966 and 6,409,924, it is expedient to dispose the separationapparatus described herein at or near the boat landing deck level 26(such that at least a portion of the sump tank 24A is within about 10feet of ocean level) since contaminants collected on the productiondecks 16, 18, 20 and 22 that may accumulate during dry weather on theinner surfaces of the conduit 28 and inner surfaces of sump tank 24A canbe separated from the water that flows from the decks to the sump tank24A for recovery and separation in accordance with the apparatus andmethods described herein.

In accordance with an important feature of the methods, apparatus andmercury removal media described herein, a downwardly extending legportion 42 of water leg 34 is operatively interconnected to, and influid communication with, one or more mercury and/or arsenicmedia-containing vessels 44. As shown in FIG. 8, the mercury removalmedia within vessel 44 captures the mercury and thereby separatesessentially all mercury from the water (less than about 10 parts permillion, preferably less than about 1 part per million mercury remains).The treated water flows through the liquid-permeable covers 76 of thecartridges 55 into the vessel 44. The treated water then flows bygravity through water exit opening 46 in the water and coalescedhydrocarbon collection vessel 44 and through exit conduit 48 back to theocean water 14.

As shown in FIGS. 8 and 9, vessel 44 includes an outer,fluid-impermeable housing 48 having a water inlet 42 interconnectedthrough the housing 48 so that mercury-contaminated water enters vessel44 and then flows through the Hg/As removal media-containing cartridges55, through a plurality of longitudinal, axial, central inlet conduits56, 56A, 56B, 56C and 56D that may form part of a header, described inmore detail hereinafter. The mercury removal media-containing cartridges55 are water-permeable by virtue of flow apertures 57, in the cartridgecover 76, that are sized sufficiently small such that the mercuryremoval media does not pass therethrough. Water entering vessel 44through inlet conduit 42 and cartridge inlet conduits 56, 56A, 56B, 56Cand 56D flows radially outwardly through the mercury removal media 45where the mercury removal media captures, and removes, the mercury fromthe contaminated water. The purified water flows through the openings 57in each liquid permeable cartridge cover 76 and collect in vessel 44.The clean water exits the vessel 44 through exit conduit 69 and throughvalve 71 and then is returned to the ocean 14 via outlet 73.

Turning to FIG. 9, another embodiment of a vessel 100 is showncontaining stacks of cartridges, one of which is shown at 102. Eachcartridge stack includes a plurality of annular cartridges 104 throughwhich a porous contaminated liquid inlet conduit 106 extends. The porousinlet conduit 106 is connected to a header 108 which is disposed withina bottom section 110 of the vessel 100, similar to the contaminatedwater inlet conduits 56, 56A, 56B, 56C and 56D shown in FIG. 8.

Turning to FIGS. 9 and 10, the header 108 is connected to amercury-contaminated water inlet 112 which includes a flange 114 whichis connected to the flange 116 of the header 108 by a plurality offasteners, such as bolts (not shown). The header is also supportedwithin the bottom structure 110 (see FIG. 9) of the vessel by aplurality of supports shown at 118. The header 108 includes a pluralityof openings 120, each of which receives a permeable conduit 106 (seeFIG. 9). In the embodiment illustrated in FIGS. 9 and 10, the header 108is connected to 23 permeable conduits and therefore supports 23 stacks102 of cartridges 104. By providing the header 108 within the bottomstructure 110 of the vessel 100, a permeable tube sheet 111 shown inFIG. 8 is not needed for collecting solids and the bottom section 110 ofthe vessel can be used to collect accumulated solids, or solids which donot pass through the outer covers 76 of the filter cartridges 104. Adrain 122 is provided for purposes of flushing out the accumulatedsolids which settle in the bottom structure 110 of the vessel 100,together with the clean water. The clean water can be passed through asolids filter 123 before being directed to the ocean through conduit125. In contrast, solids will accumulate on top of the tube sheet 111.Thus, the solids must be removed from above the tube sheet 108 using oneor more nozzle openings shown at 109 in FIG. 8. As shown in FIG. 9,these additional nozzle openings are not required in the vessel 100because the accumulated solids are easily flushed down the drain pipe122 into solids filter 123.

As shown in FIG. 9, an extremely dense number of stacks of cartridges104 is provided by the header 108. Specifically, the header 108, asshown in FIG. 10, includes 23 openings 120, and therefore 23 porousconduits 106 and therefore 23 stacks 102 of cartridges 104. Accordingly,the volumetric flow rate that can be handled by the vessel 100 issubstantially greater than the volumetric flow rate that can be handledby the vessel 44. Of course, smaller vessels with fewer stacks ofcartridges and large vessels with more stacks of cartridges areanticipated

FIGS. 11 and 12 illustrate a single cartridge 55 containing the Hg/Asremoval media 45 that is loosely packed within the canister 55 betweenliquid-permeable contaminated water inlet tube (56, 56A, 56B, 56C and56D of FIG. 6) and an outer, liquid-permeable cartridge cover 76. Asshown, the mercury removal media 45 comprises an organoclay containingsulfur.

1. A contaminant removal media for removing mercury and/or arsenic fromwater by contact comprising: an intimate mixture of A) a sulfurimpregnated organoclay and B) a sulfur-containing coupling agent-reactedlayered phyllosilicate.
 2. The contaminant removal media of claim 1,wherein the coupling agent includes a mercapto or sulfide moiety.
 3. Thecontaminant removal media of claim 1, wherein the weight percentage ofcomponents in each of the sulfur-impregnated organoclay and the couplingagent-reacted media is as follows: A) 1) organoclay: 50 to 99.5 wt. %;and 2) elemental sulfur: 0.5 to 50 wt. %; B) 1) layered phyllosilicate:50 to 99.5 wt. %; and 2) coupling agent: 0.5 to 50 wt. %.
 4. Thecontaminant removal media of claim 3 wherein the organoclay comprises alayered phyllosilicate an intercalated with a phyllosilicate intercalantagent, and wherein the percentage of components is as follows: A) 1)organoclay: 50 to 99.5 wt. %; and 2) elemental sulfur: 0.5-50 wt. %;B) 1) layered phyllosilicate: 1-90 wt. %; intercalant agent: 10-50 wt.%; and 2) coupling agent: 0.5-50 wt. %.
 5. The contaminant removal mediaof claim 4 further including an intercalant agent, and wherein theweight percentage of components is as follows: A) 1) organoclay: 50 to99.5 wt. %; and 2) elemental sulfur: 2-20 wt. %; B) 1) layeredphyllosilicate: 35-83 wt. %; intercalant agent: 15-45 wt. %; and 2)coupling agent: 2-20 wt. %.
 6. The contaminant removal media of claim 5further including an intercalant agent, and wherein the percentage ofcomponents is as follows: A) 1) organoclay: 50 to 99.5 wt. %; and 2)elemental sulfur: 3-10 wt. %; B) 1) layered phyllosilicate: 50-77 wt. %;intercalant agent: 20-40 wt. %; and 2) coupling agent: 2-12 wt. %. 7.The contaminant removal media of claim 6 further including anintercalant agent, and wherein the percentage of components is asfollows: A) 1) organoclay: 50 to 99.5 wt. %; and 2) elemental sulfur:4-6 wt. %; B) 1) layered phyllosilicate: 59-71 wt. %; intercalant agent:25-35 wt. %; and 2) coupling agent: 5-9 wt. %.
 8. The contaminantremoval media of claim 7 wherein the percentage of components is asfollows: A) 1) layered phyllosilicate: 65 wt. %; intercalant agent: 30wt. %; and 2) coupling agent: 5 wt. %; B) 1) layered phyllosilicate: 65wt. %; intercalant agent: 28 wt. %; and 2) coupling agent: 7 wt. %. 9.The contaminant removal media of claim 1, wherein the components of boththe sulfur-impregnated media and the coupling agent-reacted media arecompacted in an extruder, either as separate media or combined media.10. A method of removing mercury and/or arsenic from water comprisingcontacting the water with the contaminant removal media of claim
 1. 11.A method of removing mercury and/or arsenic from water comprisingcontacting the water with the contaminant removal media of claim
 2. 12.A method of removing mercury and/or arsenic from water comprisingcontacting the water with the contaminant removal media of claim
 3. 13.A method of removing mercury and/or arsenic from water comprisingcontacting the water with the contaminant removal media of claim
 4. 14.The mercury removal media of claim 1, wherein each of thesulfur-impregnated media and the coupling agent-reacted media has aparticle size finer than 18 mesh, U.S. Sieve Series.
 15. The mercuryremoval media of claim 14, wherein each of the sulfur-impregnated mediaand the coupling agent-reacted layered phyllosilicate has a particlesize finer than 50 mesh, U.S. Sieve Series.
 16. A contaminant removalmedia for removing mercury and/or arsenic from water by contactcomprising contacting the water with both removal media A) and B): A) anintimate mixture of a layered phyllosilicate intercalated with asurface-modifying, layer-expanding intercalant; and sulfur, and B) amixture of a layered phyllosilicate intercalated with an intercalantsurface modification agent; and a coupling agent containing a mercaptoor sulfide moiety intimately mixed for reaction of the coupling agentwith the layered phyllosilicate.
 17. A method of regeneratingcontaminated water containing organic and mercury or arseniccontaminants comprising: contacting the contaminated water with anorganoclay for removal of organic contaminants; and contacting thecontaminated water with the contaminant removal media A) and B) of claim1 for removal of mercury or arsenic contaminants.
 18. The method ofclaim 17 wherein the organoclay and each contaminant removal media arecontained in separate vessels connected in series.
 19. The method ofclaim 17 wherein the organoclay and both contaminant removal media arecontained in the same vessel.
 20. The contaminant removal media of claim1, wherein the elemental sulfur of media A) has a particle size suchthat at least 80% of the particles are finer than 18 mesh, U.S. SieveSeries.
 21. The contaminant removal media of claim 20, wherein theelemental sulfur of media A) has a particle size such that at least 80%of the particles are finer than 50 mesh, U.S. Sieve Series.
 22. Thecontaminant removal media of claim 21, wherein the elemental sulfur ofmedia A) has a particle size such that at least 80% of the particles arefiner than 70 mesh, U.S. Sieve Series.
 23. The mercury removal media ofclaim 22, wherein the elemental sulfur of media A) has a particle sizesuch that at least 80% of the particles are finer than 80 mesh, U.S.Sieve Series.
 24. The mercury removal media of claim 23, wherein theelemental sulfur of media A) has a particle size such that at least 80%of the particles are finer than 100 mesh, U.S. Sieve Series.